Typically, a navigation system includes a CD/DVD player integrated therein for retrieval and/or playback of map data, music data, video data and other type of information. A user of the navigation system can display those data on a display of the navigation system or can playback those data for listening/viewing in a vehicle.
The CD/DVD player or a DVD-ROM drive for data retrieval has an eject mechanism for ejecting a CD/DVD inserted therein. The CD/DVD is easily and readily replaced once the data in the medium is accessed, used, etc. or stored elsewhere for use. The CD/DVD is also replaced when, for example, new map data is published as an update for a road map. In those cases, the user can replace the CD/DVD by him/herself without asking a sales representative or a shop clerk of a dealership for replacement.
The navigation system is installed in a center portion of a console of a dashboard for the sake of operability, accessibility and aesthetics. However, it may be easy for a child or other unwanted user to operate the device and causes damage or the like. In this case, a child lock function for invalidating at least some operations performed on the navigation system is used to protect the navigation system from damage. For example, the navigation system disclosed in Japanese Patent Document JP-A-2000-17920 has a function that prevents unwanted operations performed on the navigation system from taking effect.
The navigation system in the vehicle is, as described above, easily accessible, and the information medium (e.g., CD/DVD etc.) in the navigation system is easily ejectable. Therefore, automobile dealerships prevent theft of the CD/DVD by removing those media from the CD/DVD drive.
However, the CD/DVD player can not be fully operated without having those media in the drive for demonstration purpose. Further, using the child lock device for preventing theft of the media is undesirable, because functions affected by the child lock device may be functions that a prospective customer wishes to try out. That is, the child lock device may reduce a customer's interest in purchasing the vehicle.